As I understand it, the House plan to repeal and replace Obamacare involves three steps. The first can go through the Senate with 51 votes because it deals with budgetary matters and can utilize the so-called "reconciliation" process.
This first step is on the table at present and it continues to subsidize health care for lower income Americans, albeit using a different mechanism. House conservatives reject it for, as I understand it, two reasons.
Reason one: they oppose government subsidy of health care for working people, period. I understand that viewpoint but find it, frankly, unrealistic politically.
Public opinion currently holds no one should be without health care because they can't afford it. Dumping perhaps millions of folks off Obamacare with no feasible alternative won't sell politically.
Reason two: they are concerned steps two and three which deal with the non-financial aspects of the new system will never pass the Senate's filibuster roadblock of 60 votes to move non-budgetary bills to a vote. This is a reasonable concern.
Doing so would require 7 or 8 Democrat senators to vote for the Obamacare replacement. Any hope they will do so rests on the notion that 10 Democrats face reelection in 2018 in states carried by Trump in 2016.
Presumably some such senators can be pressured to go along; at the moment I can think of only one. Any who do so may face a primary challenge by angry Democrats willing to lose the seat to punish a "traitor."
The other alternative for passing the remaining two steps would be a change in Senate rules essentially eliminating the filibuster. This can be done with 51 votes.
I believe there is insufficient appetite among Republican senators for this drastic step which, once taken, cannot be walked back. Senators have long time horizons. Next time they are in the minority they'll want the 60 vote requirement to keep a rein on Democrat social engineering.
In order to break the logjam, Majority Leader Mitch McConnell needs to convince conservative House members why he is confident steps two and three will pass the Senate. That will be a hard sell.
One mechanism might be to write the legislation in such fashion that none of it becomes operational until all three steps pass and are signed into law. This mechanism probably guarantees the legislation will never become law, making it a likely non-starter. I'm not certain what his Plan B might be.